Into the unknown: Exploring New Mammoth Cave

Water can spread for miles and miles underground in the network of caves of this karst landscape making water contamination a particularly difficult thing to trace. With the guidance of the Nature Conservancy's cave and karst specialist, Cory Holliday, Alexandra delves into the unseen ecosystem to find out more about importance of the watershed beneath our feet.

In July 2010, Alexandra Cousteau and her international Expedition Blue Planet team departed on a 14,500-mile journey across North America to investigate global water issues "in the backyard" of one of the world’s leading economies. Living, working and exploring water stories together, Alexandra and her team will use everything from the underwater gear invented by her grandfather to the latest in satellite technology and live social media to bring the thrill of adventure and the wonders of nature to audiences across the globe.